Defoamers for hydratable cementitious compositions

ABSTRACT

The present invention discloses additive compositions, cementitious compositions, and methods for controlling air in cementitious compositions, wherein a polyalkoxylated polyalkylene polyamine defoamer is deployed in combination with one or more air-entraining agents, such as higher alkanolamines, water-reducing agents including oxyalkylene-containing superplasticizers, or other air entraining agents.

FIELD OF THE INVENTION

This invention relates to air management in hydratable cementitiousmaterials such as concrete, and more particularly to the use of apolyalkoxylated polyalkylene polyamine defoamer in combination with oneor more air-entraining agents for controlling air in cementitiouscompositions.

BACKGROUND OF THE INVENTION

A certain amount of entrained air is necessary for improving thefreeze-thaw durability of concrete, which is a brittle material.However, the nature and extent of air entrainment must be carefullycontrolled because excessively large or unevenly spaced air voids withinthe concrete can lead to loss of freeze-thaw durability and compressivestrength. Air entraining agents such as rosins and anionic surfactantsare commonly used to control the size and spacing of air voids withinthe cementitious mix.

In European Patent EP 0 415 799 B1 (owned by the common assigneehereof), Gartner et al. taught that additions to cementitiouscompositions of a higher alkanolamine, such as triisopropanolamine(“TIPA”), enhanced late strength (e.g., at 28 days) but also increasedthe amount of air entrained in the cementitious composition. Analysis ofvarious cement samples revealed an increase in air entrainment of abouttwo percent when compared to cement that did not contain TIPA. Gartneret al. suggested using air-detraining nonionic surfactants, whichincluded phosphates (e.g., tributylphosphate), phthalates (e.g.,diisodecylphthalate), and polyoxypropylene-polyoxyethylene blockcopolymers. See EP 0 415 799 B1 at Page 6, lines 40-53.

In U.S. Pat. No. 5,156,679 (owned by the common assignee hereof),Gartner et al. taught the use of water-soluble alkylated alkanolaminesalts for detraining air in concrete. These materials includedN-alkylalkanolamine and N-alkyl-hydroxylamine. When TIPA was added to amortar mix in the amount of 0.02% by weight as part of the water ofhydration along with 0.01% by weight of dibutylamino-2-butanol (“DBAB”)as a defoamer, the mortar mix demonstrated a reduction in airentrainment (Col. 5, line 51-Col. 6, line 14).

When concrete is formed, it requires mixing of the various componentssuch as hydraulic cement, sand, gravel, water, and possibly additives toform a substantially uniform mixture. During mixing, air becomesentrapped in the composition, and much of this air remains in theresultant cured composition in the form of air voids. If air void sizeis small, the mix is said to be “air entrained.” In most instances, asmall amount of air entrainment is tolerated, and, in other instances,this is desirable for enhancing durability of the concrete in terms ofresisting freeze/thaw cycles.

However, excessive air entrainment in the hydraulic cement compositionwill cause the resultant structure to have lower compressive strengththan the mixture design is otherwise capable of attaining. There is aninverse relationship between air entrainment and compressive strength.It is generally believed that for each volume percent of air voids(bubbles) in a concrete mass, there exists a five percent loss ofcompressive strength. Hence, management of the air void content andnature is vitally important.

Water-reducing admixtures (including superplasticizers) are particularlyknown to entrain excessive air in the concrete slurry. The industry hasattempted to correct this by using air-detraining agents (otherwisecalled defoamers herein) in the concrete mix. As with the cementgrinding additives (e.g., TIPA) previously mentioned, common admixturesinclude hydrophobic materials such as nonionic surfactants with lowhydrophilic-lipophilic balance (HLB), silicone derivatives,tributylphosphate, and alkyl phthalates.

However, defoamers with high hydrophobic properties have, as aconsequence, very limited solubility in water, and are not easilyincorporated into the aqueous solutions which make up the water-reducingadmixtures. Their hydrophobic nature tends to destabilize the aqueousproduct by fostering separation of the components, and requires that thewater-reducing admixture and defoamer be stored in separate tanks andmixed immediately before use; or, alternatively, that they be pre-mixedand constantly stirred to prevent separation.

In U.S. Pat. Nos. 5,665,158 and 5,725,657 (owned by the common assigneehereof), Darwin et al. disclosed the use of oxyalkylene amine-baseddefoaming agents for use with polycarboxylate superplasticizers. Analkoxypolyoxyalkylene ammonium polymer was ionically attached to thecarboxylate portion of the comb polymer backbone to impart desired aircontrolling properties to the hydratable concrete being treated.

In U.S. Pat. No. 6,139,623 (owned by the common assignee hereof), Darwinet al. disclosed polycarboxylate superplasticizers emulsified withantifoaming agent using a surfactant to stabilize the emulsifiedsuperplasticizer and antifoaming agent. The antifoaming agent could beselected from phosphate esters (e.g., dibutylphosphate,tributylphosphate), borate esters, silicone derivates (e.g., polyalkylsiloxanes), and polyoxyalkylenes having defoaming properties.

In U.S. Pat. No. 6,858,661 (owned by the common assignee hereof), Zhanget al. disclosed a polycarboxylate water-reducer and a tertiary aminedefoamer having an average molecular weight of 100-1500 for creating astable admixture formulation and helping to achieve a controllable levelof entrained air in the concrete mix.

In U.S. Pat. No. 6,545,067 (owned by BASF), Buchner et al. disclosedmixtures of polycarboxylate superplasticizer and butoxylatedpolyalkylene polyamine as a defoamer for reducing the air pore contentof cement mixes.

In U.S. Pat. No. 6,803,396 (also owned by BASF), Gopalkrishnan et al.disclosed mixtures of polycarboxylate superplasticizer andair-detraining agents. The air detrainers were based on low molecularweight block polyether polymers described as containing ethylene oxideand propylene oxide units and described as being initiated usingreactive diamine or glycol groups.

In U.S. Pat. No. 6,569,924 (owned by MBT Holding AG), Shendy et al.disclosed the use of polycarboxylate dispersants, a water-insolubledefoamer, and a solubilizing agents for solubilizing the water-insolubledefoamer. Such solubilizing agents functioned by increasing the amountof oil component within the aqueous phase. A similar approach was takenin U.S. Pat. No. 6,875,801 wherein Shendy et al. described using aminesolubilizing agents for stabilizing water-insoluble defoamers.

Regardless of whether the defoamer is grafted onto a polymer dispersantor emulsified or rendered more water-soluble within the additivecomposition, the present inventor believes that a critical problem stillremains with avoiding phase separation within the water-based additiveformulation while retaining the efficacy of the defoamer to detrain airwithin the cementitious mixture being treated.

Accordingly, an improved defoamer additive composition is needed forimproving the stability of air-entraining additives used in cement orconcrete mixes without curtailing the effectiveness of the defoamer asan air-detraining agent. The present inventor believes that a new classof defoamers for use with air-entraining agents, such as highertrialkanolamines and water-reducing agents, is needed for controllingair content in cementitious materials, and also for providing differentdegrees of defoaming power, yet with increasing water compatability thatprovides resistance to phase separation.

SUMMARY OF THE INVENTION

In surmounting the disadvantages of the prior art, the present inventionprovides a novel and inventive additive composition for controlling airin hydratable cementitious compositions. The term “additive” is usedherein to refer to agents added at cement plants where clinker isinterground to produce cement and also to refer to “admixtures” whichare combined with cement, water, and aggregates to produce mortar orconcrete.

The present invention involves the use of a defoamer that can be usedalone with conventional air-entraining agents (e.g., higheralkanolamines such as TIPA), water-reducing agents such asoxyalkylene-containing superplasticizers), or in combination withexisting defoamers (e.g., tributyl-phosphate).

Thus, an exemplary additive composition of the present invention forcontrolling air in hydratable cementitious compositions comprises:

(A) at least one agent operative to entrain air in a hydratablecementitious composition, said at least one agent comprising a highertrialkanolamine, a lignosulfonate, a naphthalene sulfonate, a melaminesulfonate, an oxyalkylene-containing superplastizicer, anoxyalkylene-containing shrinkage reducing agent, or mixture thereof;

(B) a polyalkoxylated polyalkylene polyamine defoamer having a structurerepresented by Formula (1)

or salt thereof, or combination of said defoamer and salt thereof,wherein each of R¹, R², R³, R⁴, R⁵, R⁶, and R⁷ independently representsa hydrogen, C₁-C₄ alkyl group, —CH₂—OH, or -(AO)_(x)—R⁸ wherein AOrepresents propylene oxide (“PO”) or a mixture of PO and ethylene oxide(“EO”) wherein the molar ratio of PO to EO is at least 100:0 to 100:90;“x” represents an integer of 0 to 100; and R⁸ represents hydrogen or analkyl group; “n” represents an integer of 0 to 100; and

wherein, if “n” is 0 then the amount of EO is less than 10% by weightbased on total weight of said polyalkoxylated polyalkylene polyaminedefoamer; and

(C) the ratio of component A to component B is in the range of 5 to 100by dry weight.

An exemplary cement composition of the invention comprises a hydratablecementitious binder and the foregoing additive composition, while anexemplary method of the invention comprises combining a hydratablecementitious binder with the foregoing additive composition.

Further advantages and features of the invention may be described indetail hereinafter.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

The term “cement” as used herein includes hydratable cement which isproduced by pulverizing clinker consisting of hydraulic calciumsilicates and one or more forms of calcium sulfate (e.g., gypsum) as aninterground additive. “Mortars” are cement pastes formed with water andadditionally including fine aggregate (e.g., sand), while “concretes”are mortars which additionally include coarse aggregate (e.g., crushedstones or gravel).

The term “cementitious” as used herein refers to materials that includeor comprise cement (e.g., Portland cement) or which otherwise functionas a binder to hold together fine aggregates (e.g., sand), coarseaggregates (e.g., crushed gravel), or mixtures thereof. Typically,Portland cement is combined with one or more other supplementarycementitious materials (“SCMs”) and provided as a blend. SCMs mayinclude limestone, hydrated lime, fly ash, granulated blast furnaceslag, and silica fume, or other materials commonly included in suchcements. Cementitious materials may therefore include one or more SCMspreferably in an amount of 0%-100%, more preferably 10%-60%, based ontotal dry weight of cementitious material.

The term “hydratable” as used herein is intended to refer to cement orcementitious materials that are hardened by chemical interaction withwater. Portland cement clinker is a partially fused mass primarilycomposed of hydratable calcium silicates. The calcium silicates areessentially a mixture of tricalcium silicate (3CaO.SiO₂ “C₃S” in cementchemists notation) and dicalcium silicate (2CaO.SiO₂,“C₂S”) in which theformer is the dominant form, with lesser amounts of tricalcium aluminate(3CaO.Al₂O₃, “C₃A”) and tetracalcium aluminoferrite (4CaO.Al₂O₃.Fe₂O₃,“C₄AF”). See e.g., Dodson, Vance H., Concrete Admixtures (Van NostrandReinhold, New York N.Y. 1990), page 1.

As previously summarized, exemplary additive and cement compositions ofthe invention comprise the use of at least one agent comprising a highertrialkanolamine, lignosulfonate, a naphthalene sulfonate, a melaminesulfonate, an oxyalkylene-containing superplasticizer, anoxyalkylene-containing shrinkage reducing agent, or mixture thereof. Theterm “additive” shall be used herein to describe additives added at thecement manufacturing plant and also to describe “admixtures” which areadded to cement, water, and optional aggregates used for making cementmortars, concretes, and other cementitious materials. Preferably, theadditive compositions are aqueous liquids that may be dispensed (e.g.,pump-metered) in liquid form.

The term “higher trialkanolamine” as used herein shall refer to tertiaryamine compounds which are tri(hydroxyalkyl) amines having at least oneC₃-C₅ hydroxyalkyl, and, more preferably, at least one C₃-C₄hydroxyalkyl, group therein. The remaining (if any) hydroxyalkyl groupsof the tertiary amine can be selected from C₁-C₂ hydroxyalkyl groups(preferably C₂ hydroxyalkyl). Examples of such compounds includehydroxyethyl di(hydroxypropyl)amine, hydroxypropyldi(hydroxyethyl)amine, tri(hydroxypropyl)amine, hydroxyethyldi(hydroxy-n-butyl)amine, tri(2-hydroxybutyl)amine, hydroxybutyldi(hydroxypropyl)amine, and the like. The preferred highertrialkanolamines are triisopropanolamine (“TIPA”),N,N-bis(2-hydroxyethyl)-N-(2-hydroxypropyl)amine (“DEIPA”),N,N-bis(2-hydroxypropyl)-N-(hydroxyethyl)amine (“EDIPA”), andtri(2-hydroxybutyl) amine. Mixtures of such higher trialkanolamines canbe used, and any of these or a combination of these can be used with oneor more of triethanolamine (TEA), diethanolamine (DEA),monoethanolamine, or mixtures thereof. When used as a grinding additivefor Portland cement or blended cement, the higher trialkanolamines canbe added in an amount up to 2%, preferably up to 0.1%, and mostpreferably between 0.005%-0.03% based on weight of the cement. Inparticular, TIPA is known for use as a late strength enhancer.

The terms “lignosulfonate,” “naphthalene sulfonate,” “melaminesulfonate,” and “oxyalkylene-containing superplasticizer” are usedherein to refer to water-reducing agents (“WRA”) known to entrain air. A“lignosulfonate” WRA includes alkali metal or alkaline earth salts oflignosulfonic acid, such as calcium lignosulfonate, which is acommonly-used WRA. A “naphthalene sulfonate” WRA includes an alkalimetal salt of a sulfonated naphthalene-formaldehyde condensate; while a“melamine sulfonate” WRA includes an alkali metal salt of a sulfonatedmelamine-formaldehyde condensate.

References to compounds in their salt form may be understood to includereference to their acid form, and vice-versa, because it may be the casethat both acid and salt forms can co-exist within the aqueousenvironment. Similarly, it may also be understood that reference tocompounds in their amine form may be understood to include reference totheir ammonium form, and vice-versa.

The term “oxyalkylene-containing superplasticizer” will refer towater-reducing agents, typically comb polymers comprised ofpolycarboxylic acid or partial esters to which are attached pendantpolyoxyalkylene groups. Such oxyalkylene groups include ethylene oxide(EO), propylene oxide (PO), and butylene oxide. Suchoxyalkylene-containing superplasticizer will be any of those customarilyused in the cement and concrete industries. For example, polymericsuperplasticizers which are comb polymers having a carbon-containingbackbone to which are attached polyoxyalkylene groups through amide,imide, ester, and/or ether linkages are contemplated for use in thepresent invention. Other examples of oxyalkylene-containingsuperplasticizers include copolymers of acrylic or methacrylic acid withthe reaction product of acrylic acid or methacrylic acid withpolyalkyleneglycol monomethyl ether. A further example ofoxyalkylene-containing superplasticizers includes copolymers of acrylicacid or methacrylic acid with polyalkoxylated alcohols with typicalalcohol chain lengths of C₃ to C₂₀.

Generally, the amount of air-entraining WRA used in the invention whichis to be added to cement compositions will be in amounts of at leastabout 0.005 weight percent, and usually in the range of 0.005 to about 5weight percent, and preferably 0.03 weight percent to about 1 weightpercent based on the total weight of the cement or cementitiouscomposition.

The term “oxyalkylene-containing shrinkage reducing agent” (hereinafteroxyalkylene-containing “SRA”) refers to additives which are designed toinhibit drying shrinkage of cementitious compositions by maintaining orincreasing air void content of the cementitious composition. Examples ofoxyalkylene-containing SRAs and SRA formulated compositions aredisclosed in U.S. Pat. Nos. 5,556,460; 5,604,273; 5,618,344; 5,779,788;and 5,622,558; 5,603,760; and 6,277,191, all of which are incorporatedherein by reference. While many of the SRA compositions and formulationsdescribed in these patent references are useful for maintaining orcontrolling air content, the inventor believes that the use of thepolyalkoxylated polyalkylene polyamine defoamer of the present inventioncan expand design possibilities of oxyalkylene SRAs in that smaller,more uniform air voids can be formed.

Thus, an exemplary additive composition of the invention for controllingair in hydratable cementitious compositions comprises:

(A) at least one agent operative to entrain air in a hydratablecementitious composition, said at least one agent comprising a highertrialkanolamine, a lignosulfonate, a naphthalene sulfonate, a melaminesulfonate, an oxyalkylene-containing superplastizicer, anoxyalkylene-containing shrinkage reducing agent, or mixture thereof; and

(B) a polyalkoxylated polyalkylene polyamine defoamer having a structurerepresented by Formula (1)

or salt thereof, or combination of said defoamer and salt thereof,wherein each of R¹, R², R³, R⁴, R⁵, R⁶, and R⁷ independently representsa hydrogen, C₁-C₄ alkyl group, —CH₂—OH, or -(AO)_(x)—R⁸ wherein AOrepresents propylene oxide (“PO”) or a mixture of PO and ethylene oxide(“EO”) wherein the molar ratio of PO to EO is at least 100:0 to 100:90;“x” represents an integer of 0 to 100; and R⁸ represents hydrogen or analkyl group; “n” represents an integer of 0 to 100; and

wherein, if “n” is 0 then the amount of EO is less than 10% by weightbased on total weight of said polyalkoxylated polyalkylene polyaminedefoamer; and

(C) the ratio of component A to component B is in the range of 5 to 100by dry weight (and more preferably in the range of 14 to 70, and mostpreferably in the range of 20 to 50).

In preferred exemplary embodiments, the defoamer is made bypolyalkoxylation of a polyalkylene polyamine. Exemplary polyalkylenepolyamines suitable for use in the present invention include, but arenot limited to, ethylene diamine, diethylene triamine, triethylenetetramine, tetraethylene pentamine, pentaethylene hexamine, propylenediamine, dipropylene triamine, tripropylene tetramine, tetrapropylenepentamine, pentapropylene hexamine, N,N-dimethylethylene diamine,N,N′-dimethylethylene diamine, N,N-dimethylpropylene diamine,N,N′-dimethylpropylene diamine, N,N-diethylethylene diamine,N,N′-diethylethylene diamine, N,N-diethylpropylene diamine,N,N′-diethylpropylene diamine. More preferred of these polyalkylenepolyamines are ethylene diamine, diethylene triamine, triethylenetetramine, or mixtures thereof, with the most preferred being diethylenetriamine.

In further exemplary embodiments, the polyalkylene polyamine may bealkoxylated by reacting it with ethylene oxide, propylene oxide, or ahigher alkylene oxide. In still further exemplary embodiments, thepolyalkylene polyamine may be alkoxylated by reacting it with ethyleneoxide and propylene oxide, wherein the molar ratio of propylene oxide toethylene oxide is greater than 1. In another preferred embodiment, theamount of ethylene oxide groups is in the range of 0%-40% based on totalweight of the polyethers, whereas the amount of polypropylene oxidegroups is in the range of 60%-100% based on total weight of thepolyethers.

In further exemplary embodiments, the polyalkoxylated polyalkylenepolyamine defoamer of component B has a number-average molecular weightof 500-7000. More preferably, the number-average molecular weight is1000-5000; and most preferably the number-average molecular weight is2000-3500.

In further exemplary embodiments, the polyalkoxylated polyalkylenepolyamine defoamer of component B is neutralized with an acid. The acidmay be selected from formic acid, acetic acid, propionic acid,hydrochloric acid, nitric acid, sulfuric acid, or a mixture thereof.Preferably, the acid is formic acid or acetic acid. An exemplary acidwhich may be used for neutralizing the polyalkoxylated polyalkylenepolyamine defoamer of component B may also be an oxyalkylene-containingsuperplasticizer.

The present invention also provides a method for controlling air in acementitious composition which comprises combining a hydratablecementitious binder, such as cement (which may include supplementalcementitious materials), with the aforementioned polyalkoxylatedpolyalkylene polyamine defoamer.

Thus, an exemplary method of the present invention controlling air incementitious compositions comprises combining a hydratable cementitiouscomposition with an additive having

(A) at least one agent operative to entrain air in a hydratablecementitious composition, said at least one agent comprising a highertrialkanolamine, a lignosulfonate, a naphthalene sulfonate, a melaminesulfonate, an oxyalkylene-containing superplastizicer, anoxyalkylene-containing shrinkage reducing agent, or mixture thereof;

(B) a polyalkoxylated polyalkylene polyamine defoamer having a structurerepresented by Formula (1)

or salt thereof, or combination of said defoamer and salt thereof,wherein each of R¹, R², R³, R⁴, R⁵, R⁶, and R⁷ independently representsa hydrogen, C₁-C₄ alkyl group, —CH₂—OH, or -(AO)_(x)—R⁸ wherein AOrepresents propylene oxide (“PO”) or a mixture of PO and ethylene oxide(“EO”) wherein the molar ratio of PO to EO is at least 100:0 to 100:90;“x” represents an integer of 0 to 100; and R⁸ represents hydrogen or analkyl group; “n” represents an integer of 0 to 100; and

wherein, if “n” is 0 then the amount of EO is less than 10% by weightbased on total weight of said polyalkoxylated polyalkylene polyaminedefoamer; and

(C) the ratio of component A to component B is in the range of 5 to 100by dry weight (and more preferably in the range of 14-70, and mostpreferably in the range of 20-50).

The present invention also pertains to cement compositions comprising ahydratable cementitious binder and the aforementioned polyalkoxylatedpolyalkylene polyamine defoamer which may be in amine form, ammoniumsalt form, or simultaneously in both forms, depending upon pH leveland/or other factors.

The amount of the polyalkoxylated polyalkylene defoamer used will dependon the amount and nature of the one or more air-entraining agents used(Component (A)), but typically could be in the range of 0.05-5.0% basedon weight of hydratable cement in the cementitious composition beingtreated.

In further exemplary methods and compositions of the inventions, one ormore conventional defoamers may be combined with the polyalkoxylatedpolyalkylene polyamine in exemplary additive compositions, cementcompositions and methods of the invention. Conventional defoamers thatare contemplated for use in the present invention includetributylphosphate. Another such defoamer is bishydroxylpropyl tallowamine (a tertiary amine defoamer represented by the structural formulaR¹NR²R³ wherein R¹ is hydrophobic and represents a C₈-C₂₅ groupcomprising a linear or branched alkyl, alkene, alkyne, alcohol, ester oroxyalkylene group (e.g., polyoxyalkylene) represented by the formulaR⁴-(AO)_(n)— or R⁴—(OA)_(n)- wherein R⁴ represents hydrogen or a C₁ toC₂₅ alkyl group, A represents a C₁ to C₆ alkyl group and “n” is aninteger of 1 to 4; and R² and R³ each represent a C₁-C₆ group comprisinga branched or linear alkyl, alkene, alkyne, alcohol, ester oroxyalkylene group (e.g., polyoxyalkylene) represented by the formulaeR⁴-(AO)_(n)— or R⁴(OA)_(n)- wherein R⁴ represents hydrogen or a C₁-C₂₅alkyl group, A represents a C₁ to C₆ alkyl group, and “n” is an integerof 1 to 4; and wherein the average molecular weight of the tertiaryamine defoamer is 100-1500 and more preferably 200-750.

Further exemplary defoamers include oxyalkylene amines. The generalcomposition can be represented by structural formula X₂N(BO)_(z)Rwherein X represents hydrogen, (BO)_(z)R, or mixtures thereof; Rrepresents hydrogen, a C₁-C₁₀ alkyl group, or BNH₂ wherein B representsa C₂-C₁₀ alkylene group; and z represents an integer from 5 to 200.

Further exemplary defoamers may also be selected from the groupconsisting of a composition represented by the formula (PO)(O—R)₃wherein R is a C₂-C₂₀ alkyl group, a borate ester, a siliconederivative, and EO/PO type defoamer. Still further exemplary defoamersmay include ceto-stearyl alcohol ethoxylates and ceto-oleyl alcoholethoxylates, specifically ethoxylated and proproxylated linear primaryC₁₆-C₁₈ alcohols.

While the invention is described herein using a limited number ofembodiments, these specific embodiments are not intended to limit thescope of the invention as otherwise described and claimed herein.Modification and variations from the described embodiments exist. Morespecifically, the following examples are given as a specificillustration of embodiments of the claimed invention. It should beunderstood that the invention is not limited to the specific details setforth in the examples.

Example 1

An aqueous mixture of a polycarboxylate dispersant and polyalkoxylatedpolyethylene polyamine was prepared to yield a solution wherein solidscomprised 25% to 40% solution by total weight. The polymeric dispersantcomprised a backbone having polycarboxylate groups and pendantpolyethylene oxide groups. Polyethylene polyamines having differentdegrees of polypropoxylation, indicated in terms of the number of molesof propylene oxide per mole of polyamine, are provided in Table 1 below.

TABLE 1 Additive Propylene oxide/ sample Polyamine polyamine (mol/mol) 1Ethylenediamine 40 2 Ethylenediamine 50 3 Diethylene triamine 40 4Diethylene triamine 45 5 Diethylene triamine 50 6 Triethylene tetramine40

In these experiments, polycarboxylate and polypropoxylated polyaminewere mixed together at various weight ratios ranging from 20 to 50; thetotal concentration was 25 to 40 wt % in water. Each of the solutionswas stirred for 15 to 30 minutes at ambient temperature and the pH offinal solution ranged from 4˜5. After being stored for 60 days atambient conditions, the resultant solutions did not show any phaseseparation, indicating good storage stability.

Example 2

In this example, the defoaming property of various polypropoxylatedpolyamine additives was evaluated in a standard mortar test for slumpand air content. Ordinary Portland cement X was used at asand/cement/water ratio of 3/1/0.5. All tests were carried out in thepresence of polycarboxylate dispersant A and an air-entraining agent.The dose of the dispersant was 0.13% by weight of cement and the ratioof dispersant to additive was 33:1 by weight. The air-entraining agentis commercially available from Grace Construction Products, Cambridge,Mass. under the trade name DAREX® II AEA. The air content was measuredin accordance with ASTM C 185 and the workability was calculated usingthe equation,

Workability=slump+(flow 1+flow 2)/2−100

Three different polypropoxylated polyamines were compared with thecontrol and the results are shown in Table 2.

TABLE 2 Workability Air content Additive (mm) (%) None 197 19.7 1 21010.2 3 216 11.0 6 215 11.0As compared to the control mix without additive, the lower airpercentages for mixes using the additives clearly indicate that thepolypropoxylated polyamines functioned as effective defoamers. Thedecreased air content also reflected in an increase in workability.

Example 3

The mortar test protocol described in Example 2 was repeated, exceptthat ordinary Portland cement Y and polycarboxylate dispersant B wereused. Five different defoamers were evaluated at different weight ratiosto the polycarboxylate dispersant. In addition, the change in aircontent was measured as a function of time. The results are shown inTable 3.

TABLE 3 Dis- Air Air Air persant/ Workability Content % Content %Content % Additive Additve (mm) at 9 min. at 25 min. at 40 min. 1 29 21916.4 14.1 11.6 2 40 221 11.5 10.3 8.7 3 33 218 17.8 15.5 12.7 5 33 21111.7 10.8 9.0 6 33 225 12.4 10.8 9.5The results in this example indicate that the air content can betailored through a combination of selection of the type of polyalkylenepolyamine, degree of polypropoxylation, and its concentration relativeto the amount of dispersant.

Example 4

This example illustrates the effectiveness of the polypropoxylateddiethylene triamine as a defoamer for three different types ofpolycarboxylate dispersants in concrete. When the defoamer was used, thedispersant and defoamer were mixed together at a weight ratio of 33:1.

Concrete mixes were fabricated using the following proportions: Portlandcement X in the amount of 611 lb/yd³, fine aggregate in the amount of1330 lb/yd³, coarse aggregate in the amount of 1650 lb/yd³, and water inthe amount of 278 lb/yd³. Air content was tested in accordance with ASTMC231-97. Other concrete properties such as slump, strength and set timewere tested to confirm that the concrete was in a reasonable range forexperimental purposes. Both slump and air content were measured at 9minute mark and the results are summarized in Table 4.

TABLE 4 Polycarboxylate % added to Slump Dispersant (type) CementAdditive (inches) Air (%) B 0.12 none 7.50 6.4 B 0.12 4 6.00 3.3 C 0.12none 7.75 8.7 C 0.12 4 7.00 4.2 D 0.12 none 8.75 7.3 C 0.12 4 7.50 3.6Although each polycarboxylate dispersant entrapped different amount ofair, the results in Table 4 clearly indicate that polypropoxylateddiethylene triamine effectively reduced the air content by about 50%.

Example 5

This example demonstrates the function of polypropoxylated diethylenetriamine and polypropoxylated triethylene tetramine as defoamer inair-entrained concrete.

The concrete test protocol was similar to that used in Example 4, exceptthat a conventional air-entraining agent was also incorporated. Acommercial air-entraining agent (commercially available from GraceConstruction Products, Cambridge, Mass., under the trade name DARAVAIR®1000) was used at 0.75 oz/cwt of cement.

Also in this example, polycarboxylate dispersant B was employed at thedosage of 0.11% by weight of cement and its weight ratio to additive wasfixed at 50:1. Table 5 summarizes the results.

TABLE 5 Polycarboxylate % added to Slump Dispersant (type) CementAdditive (inches) Air (%) B 0.11 none 8.75 8.8 B 0.11 3 8.00 5.8 B 0.115 7.75 4.9 B 0.11 6 8.00 6.2The results in this table indicate that all three additives exhibited anair detraining (defoaming) ability in air-entrained concrete, and thatfor the same diamine, the air detraining power also increased withincreasing degree of polypropoxylation.

Example 6

The defoaming effects of polypropoxylated ethylene diamine andpolypropoxylated diethylene triamine were evaluated as a function oftime in air-entrained concrete. The test protocol of Example 5 was used,and both slump and air content were measured at 9, 25, and 40 minutemarks. An air-entraining agent, commercially available from GraceConstruction Products under the trade name DAREX® II AEA, was used at adosage of 0.20 oz/cwt of cement. Aqueous solutions of polycarboxylatedispersant B and additive were made at a weight ratio of 33:1. Theresults of the experiments are tabulated in Table 6.

TABLE 6 Slump (inches) at Air Content (%) at Dispersant/ 9 25 40 9 25 40Additive Additive min. min. min. min. min. min. none 9.75 7.75 6.75 14.812.0 10.4 1 33 9.00 7.75 6.25 8.9 8.1 7.3 3 33 9.25 8.00 7.00 9.3 8.98.3Compared to the control mix without additive, both polypropoxylatedethylene diamine and polypropoxylated diethylene triamine clearlydemonstrated their defoaming properties over the course of theexperiments.

The foregoing example and embodiments were present for illustrativepurposes only and not intended to limit the scope of the invention.

1. A composition for controlling air in hydratable cementitiouscompositions, comprising: (A) at least one agent operative to entrainair in a hydratable cementitious composition, said at least one agentcomprising a higher trialkanolamine, a lignosulfonate, a naphthalenesulfonate, a melamine sulfonate, an oxyalkylene-containingsuperplastizicer, an oxyalkylene-containing shrinkage reducing agent, ormixture thereof; (B) a polyalkoxylated polyalkylene polyamine defoamerhaving a structure represented by Formula (1)

or salt thereof, or combination of said defoamer and salt thereof,wherein each of R¹, R², R³, R⁴, R⁵, R⁶, and R⁷ independently representsa hydrogen, C₁-C₄ alkyl group, —CH₂—OH, or -(AO)_(x)—R⁸ wherein AOrepresents propylene oxide (“PO”) or a mixture of PO and ethylene oxide(“EO”) wherein the molar ratio of PO to EO is at least 100:0 to 100:90;“x” represents an integer of 0 to 100; and R⁸ represents hydrogen or analkyl group; “n” represents an integer of 0 to 100; and wherein, if “n”is 0 then the amount of EO is less than 10% by weight based on totalweight of said polyalkoxylated polyalkylene polyamine defoamer; and (C)The ratio of component A to component B is in the range of 5 to 100 bydry weight.
 2. The composition of claim 1 wherein said defoamer is madeby polyalkoxylation of a polyalkylene polyamine.
 3. The composition ofclaim 2 wherein said polyalkylene polyamine is selected from the groupconsisting of ethylene diamine, diethylene triamine, triethylenetetramine, tetraethylene pentamine, pentaethylene hexamine, propylenediamine, dipropylene triamine, tripropylene tetramine, tetrapropylenepentamine, pentapropylene hexamine, N,N-dimethylethylene diamine,N,N′-dimethylethylene diamine, N,N-dimethylpropylene diamine,N,N′-dimethylpropylene diamine, N,N-diethylethylene diamine,N,N′-diethylethylene diamine, N,N-diethylpropylene diamine,N,N′-diethylpropylene diamine.
 4. The composition of claim 2 whereinsaid polyalkylene polyamine is ethylene diamine, diethylene triamine,triethylene tetramine, or mixture thereof.
 5. The composition of claim 2wherein said polyalkylene polyamine is diethylene triamine.
 6. Thecomposition of claim 1 wherein said polyalkylene polyamine isalkoxylated by reacting the polyalkyklene polyamine with ethylene oxide,propylene oxide, or higher alkylene oxide.
 7. The composition of claim 1wherein said polyoxyalklene polyamine is alkoxylated by reacting thepolyalkylene polyamine with ethylene oxide and propylene oxide, whereinthe molar ratio of propylene oxide to ethylene oxide is greater than 1.8. The composition of claim 1 wherein “x” is an integer of 4 to
 100. 9.The composition of claim 1 wherein “x” is an integer of 20 to
 80. 10.The composition of claim 1 wherein “x” is an integer of 35 to
 60. 11.The composition of claim 1 wherein said polyalkoxylated polyalkylenepolyamine defoamer of component B has a number-average molecular weightof 500-7,000.
 12. The composition of claim 1 wherein saidpolyalkoxylated polyalkylene polyamine defoamer of component B has anumber-average molecular weight of 1,000-5,000.
 13. The composition ofclaim 1 wherein said polyalkoxylated polyalkylene polyamine defoamer ofcomponent B has a number-average molecular weight of 2,000-3,500. 14.The composition of claim 1 wherein the ratio of component A to componentB is in the range of 14 to 70 by percentage weight based on total weightof said composition for controlling air.
 15. The composition of claim 1wherein the ratio of component A to component B is in the range of 20 to50 by percentage weight based on total weight of said composition forcontrolling air.
 16. The composition of claim 1 wherein saidpolyalkoxylated polyalkylene polyamine is neutralized with an acid. 17.The composition of claim 16 wherein said acid is selected from formicacid, acetic acid, propionic acid, hydrochloric acid, nitric acid,sulfuric acid, or a mixture thereof.
 18. The composition of claim 16wherein said acid is formic acid or acetic acid.
 19. The composition ofclaim 16 wherein said acid is an oxyalkylene-containingsuperplasticizer.
 20. A method for modifying a cementitious composition,comprising: combining with a hydratable cementitious binder thecomposition of claim
 1. 21. A cement composition comprising a hydratablecementitious binder and the composition of claim 1.